feat: generate and edit conversation images across runtimes

Add model-controlled image invocation and read-only runtime assignments. Route image tools through Main so accepted operations retain their originating conversation when chat runtimes change, with saved references, cancellation, and manual recovery.

Keep Node hashing outside browser-shared contracts to restore production builds. Validation includes the production build, typecheck, lint, focused regressions, real Host transport checks, and two successful real image requests. Full UI-driven runtime switching acceptance remains documented as pending.

Release note: 开启图片模型的会话调用后，聊天助手可调用图片生成与编辑工具，Runtime 分配自动管理。图片成果保存在原会话，可继续修改，并独立显示生成状态和取消入口。

src/agent-daemon/runtime-acp-backend.ts

@@ -1,4 +1,6 @@
 import { z } from 'zod'
+import { AgentImageToolMcp } from './image-tool-mcp'
+import { remoteImageToolMcpName } from '../shared/remote-image-tool-node'
 import { remoteQuestionResponseSchema } from '../shared/remote-question-contracts'
 import { createHash } from 'node:crypto'
 import {
@@ -338,6 +340,7 @@ type BindingState = {
   ownedPromptStartTimer?: NodeJS.Timeout
   modelBridgePolicy?: ModelBridgePolicy
   modelBridgeClient?: ModelBridgeBlobClient
+  imageTool?: AgentImageToolMcp
   modelBridgeBroker?: ModelBridgeBrokerServer
   ownedAcp?: AgentOwnedAcpPrompt
   workspaceDirectory?: string
@@ -558,6 +561,18 @@ export class RuntimeAcpBackend {
         'identity'
       )
     }
+    const imageBinding = [...this.#bindings.values()].find(binding =>
+      binding.controllerId === context.controller.controllerId &&
+      binding.controllerGeneration === context.controller.generation &&
+      binding.connectionId === context.controller.connectionId &&
+      binding.activeOperationId !== undefined &&
+      binding.imageTool?.descriptor.channelId === frame.header.channelId &&
+      binding.imageTool.descriptor.channelEpoch === frame.header.channelEpoch &&
+      context.channelId === frame.header.channelId)
+    if (imageBinding) {
+      imageBinding.imageTool!.onReply(frame.payload)
+      return
+    }
     const matches = [...this.#bindings.values()].filter(
       (binding) =>
         binding.controllerId === context.controller.controllerId &&
@@ -613,10 +628,10 @@ export class RuntimeAcpBackend {
         binding.controllerId === controller.controllerId &&
         binding.controllerGeneration === controller.generation &&
         binding.connectionId === controller.connectionId &&
-        binding.modelBridgeClient?.binding.channelId ===
-          frame.header.channelId &&
-        binding.modelBridgeClient.binding.channelEpoch ===
-          frame.header.channelEpoch &&
+        ((binding.modelBridgeClient?.binding.channelId === frame.header.channelId &&
+          binding.modelBridgeClient.binding.channelEpoch === frame.header.channelEpoch) ||
+          (binding.imageTool?.descriptor.channelId === frame.header.channelId &&
+          binding.imageTool.descriptor.channelEpoch === frame.header.channelEpoch)) &&
         frame.header.connectionId === binding.connectionId &&
         frame.header.generation === binding.controllerGeneration
     )
@@ -1140,11 +1155,37 @@ export class RuntimeAcpBackend {
         }
       }
     }
+    if (preparation.imageTool && (preparation.workMode !== 'execute' || !this.#options.blobSink)) {
+      throw new RuntimeAcpBackendError('Image tools require Execute and a desktop transport', 'identity')
+    }
     if (requestedModelBridgePolicy !== undefined) {
       await this.#startModelBridge(binding, preparation, workspace)
     }
     const acceptedAt = new Date(this.#now()).toISOString()
+    binding.imageTool?.close()
+    binding.imageTool = undefined
+    if (preparation.imageTool) {
+      let sequence = 0n
+      const imageTool = new AgentImageToolMcp(preparation.imageTool, async payload => {
+        if (binding.activeOperationId !== preparation.operationId || binding.transportState === 'detached') {
+          throw new Error('Image tool prompt is no longer connected')
+        }
+        await this.#options.blobSink!({
+          header: {
+            protocolMajor: AGENT_PROTOCOL_VERSION.major, protocolMinor: AGENT_PROTOCOL_VERSION.minor,
+            kind: 'blob', direction: 'agent-to-main',
+            connectionId: binding.connectionId, generation: binding.controllerGeneration,
+            channelId: preparation.imageTool!.channelId, channelEpoch: preparation.imageTool!.channelEpoch,
+            sequence: String(++sequence), payloadLength: payload.byteLength
+          }, payload
+        }, { bindingId: binding.request.bindingId, controllerId: binding.controllerId,
+          controllerGeneration: binding.controllerGeneration })
+      })
+      binding.imageTool = imageTool
+      await imageTool.start()
+    }
     const acceptance = remotePromptOperationAcceptanceSchema.parse({
+      ...(binding.imageTool?.url ? { imageToolUrl: binding.imageTool.url } : {}),
       bindingId: preparation.bindingId,
       operationId: preparation.operationId,
       requestId: preparation.requestId,
@@ -1448,6 +1489,9 @@ export class RuntimeAcpBackend {
         bindingId: binding.request.bindingId,
         controllerId: binding.controllerId,
         workspaceDirectory: binding.workspaceDirectory,
+        mcpServers: () => binding.imageTool?.url ? [{
+          type: 'http', name: remoteImageToolMcpName(binding.request.bindingId), url: binding.imageTool.url, headers: []
+        }] : [],
         ...(binding.modelBridgePolicy === undefined
           ? {}
           : {
@@ -1461,7 +1505,8 @@ export class RuntimeAcpBackend {
           transport: binding.sharedProcess.transport,
           prepareSession: async (sessionId: string, operationId: string, workMode: 'ask' | 'execute') => {
             await binding.sharedProcess!.transport.setModelRoute(
-              sessionId, operationId, binding.modelBridgeBroker!.socketPath, workMode
+              sessionId, operationId, binding.modelBridgeBroker!.socketPath, workMode,
+              binding.imageTool ? remoteImageToolMcpName(binding.request.bindingId) : undefined
             )
           }
         } : {}),
@@ -1816,6 +1861,8 @@ export class RuntimeAcpBackend {
     poisonIfActive: boolean,
     preserveRuntime = false
   ): Promise<void> {
+    binding.imageTool?.close()
+    binding.imageTool = undefined
     const broker = binding.modelBridgeBroker
     const client = binding.modelBridgeClient
     binding.modelBridgeBroker = undefined
@@ -2141,6 +2188,8 @@ export class RuntimeAcpBackend {
       return
     }
     binding.transportState = 'detached'
+    binding.imageTool?.close()
+    binding.imageTool = undefined
     if (binding.modelBridgeClient !== undefined) {
       await this.#closeModelBridge(binding, false, true).catch(
         () => undefined